Thermographic dry copying machine



Nov. 23, 1965 Filed Dec. 8 1964 3 Sheets-Sheet 1 FIGQ I 22: net;

INVENTORS 47 MARVIN l. MINDELL O gQLLIAM. gau s c v JR.

CARL Fl G IO Nov. 23, 1965 M. l. MINDELL ETAL THERMOGRAPHIC DRY COPYING MACHINE 3 Sheets-Sheet 2 Filed Dec. 8 1964 NOE CH JR.

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5L %L Y IIIO TE R D U M m m WMME W J R WH N L AZII l R N o WMA W L vi 2 L 0. Y B IO 2 HIIJJ l 00 W E 2 Q/ m M L r N Nov. 23, 1965 M. l. MINDELL ETAL 3,219,794

THERMOGRAPHIG DRY COPYING MACHINE 3 Sheets-Sheet 3 Filed Dec. 8 1964 INVENTORS MARVIN I.MINDELL WILLIAM JJREUSCH JR. CARL R. EMBURY m OE 3,219,794 THERMUGRAPHKC DRY CUPYHNG MACHENE Marvin T. Mindell, Great Neck, and William J. Reusch, In, Huntington, N.Y., and Carl R. Embury, Maywood, N.Zi., assignors to Viewlex, lino, Holbrook, NDY.

Filed Dec. 8, 1064, Ser. No. 416,715 6 Gainis. (till. 2ll9--2]l6) This invention relates to copy machines and more particularly to dry copy machines using heat.

Dry copy machines generally use intense heat to transfer the image from the original paper to a heat sensitive copy paper either directly or through an intermediate carbon or wax paper.

One of the primary problems in a dry copy machine is to control the intense heat. The heat lamp is generally a long thin quartz lamp which is enclosed in a reflector which focuses on the line of tangency of the paper handling rollers. The lamp is preferably rated at 1,000 to 1,500 watts and provides a very intense heat. Means are provided to operate the lamp only during the passage of the papers past the focal line of the lamp.

The lamp is stationary and is enclosed in a glass roller. The paper is passed between a glass roller and a pressure roller which may be of neoprene, silicone rubber, fluorosilicone rubber, Teflon or other heat resistant material.

Due to the internal heat buildup as the machine is run, the entire machine heats up slowly so that the speed of the paper travel has to be controlled to provide uniform copy density. The machine can be operated at a given setting for approximately 8 to 10 initial consecutive copies before a slight change in paper speed setting is required. The machine may be operated at this setting for several additional copies prior to requiring a similar compensating adjustment.

Another problem is when the rollers are stopped, if the temperature of the glass roller is high enough, it will cause indentation of the pressure roller and hot spots or lines on the rollers also cause dark spots or lines on the copy. Means are therefore provided to automatically rotate the rollers until they are sufficiently cool even after the machine is turned off.

The motor is a universal motor. The motor is run on pulsating D.C. during the copying process since it is important to control speed of the motor and therefore, the application of heat to the papers very carefully. This is necessary to compensate for different types of copy media as well as for an increase of the temperature inside the machine as the machine heats up. The electronic DC. motor speed control is provided by an SCR type silicon controlled rectifier circuit. The applied heat must be uniform across the width of the copy and speed must be constant past the heat source to provide uniform copies.

An idle position is provided on the motor switch to keep the motor and rollers idling during the period when the paper is not running through the machine. The purpose of this is to eliminate hot spots on the glass roller which would be caused by stopping the glass roller with a section of the roller in close proximity to the hot lamp assembly. Since the glass roller is in contact with the pressure roller the heat at the point of contact with the glass roller cannot easily dissipate so that it is liable to remain hot and over expose the copy material at this point as well as burn the pressure roller or cause deformation of the pressure roller.

Another feature of the invention is the guiding of the paper through an S-bend. In prior machines, the papers are inserted on the bottom of the glass roller and make a 90 bend and come out the top of the machine. It has been found that this relatively sharp bend causes a slippage between copy medium, transfer paper and copy original due to the difference in radius between the papers.

nited States Patent 3,219,794 Patented Nov. 23, 1965 ice This occurs at the focal point of the entire operation and causes blurring of the image especially when using the carbon transfer sheets.

The present device only bends the paper about 45 and then bends at the opposite direction in an elongated S- curve so that the potential slippage is compensated for by a reversal of the curve since one paper will have the large radius on the glass roller and the other on the pressure or friction roller. The paper is then guided out the rear top of the machine.

The machine is cooled by the cylindrical turbine fan which is located at the back of the machine. The air is taken in the back of the machine and pushed out the front sides and bottom of the machine. The fan prevents the casing of the machine from becoming too hot but does not have sufficient power to completely control heating of the glass roller. Special baffles are provided to send air along the floor of the machine and into contact with the glass roller.

The motor and fan are first turned on. The paper is then inserted and the leading edge triggers one portion of a sensing finger which causes the lamp to go on and the motor to switch from idle to controlled speed. The lamp is turned off and the motor switched to idle speed, by the other portion of the sensing finger which is released by the trailing edge of the papers.

In order to avoid hot spots on the glass roller which might cause print striping of the pressure roller, the rollers are arranged to rotate after the machine is turned off by the main switch by means of a thermostat in parallel with the motor .pole of the main switch. This keeps the rollers rotating until the lamp reflector assembly drops to a temperature which will not cause any print striping or indentations of the pressure roller.

Accordingly, a principal object of the invention is to provide new and improved copy means and methods.

Another object of the invention is to provide new and improved copy means and methods using heat.

Another object of the invention is to provide new and improved dry copy means having new and improved temperature control means to provide uniform copies.

Another object of the invention is to provide new and improved dry copy means having new and improved means to control the speed of the paper to provide uniform copies.

Another object of the invention is to provide new and improved dry copy means having means to minimize slippage of the papers.

Another object of the invention is to provide new and improved dry copy means having means to prevent hot spots or lines on the rollers comprising means to keep the roller moving after the machine is shut off until the roller temperature falls to a predetermined temperature.

Another object of the invention is to provide new and improved dry copy means where the roller is driven by electronic DC. motor control means comprising a silicon controlled rectifier.

Another object of the invention is to provide new and improved dry copy means eliminating the use of relays.

Another object of the invention is to provide new and improved means having means to turn off the heat lamp in the event that the roller is stopped by jamming or overloading.

Another object of the invention is to provide new and improved dry copy means including new and improved fan and baffle means.

Another object of the invention is to provide new and improved dry copy means including motor control, means to vary the paper speed to maintain uniform copies, if the internal temperature of the machine varies.

Another object of the invention is to provide new and =1) improved dry copy machines comprising a stationary elongated heat lamp, means to adjust the position of said lamp, a hollow glass roller, means to rotatably mount said glass roller enclosing said lamp, a friction roller mounted in driven engagement with said glass roller, means to focus the heat from said lamp along the line of said tangency of said rollers, means to rotate said rollers comprising, a universal motor, means to control the speed of said motor, means to guide papers between said rollers and sensing means connected to energize said lamp only when said paper is passing between said rollers.

These and other objects of the invention will be apparent from the following specification and drawings of which:

FIGURE 1 is a perspective view of the machine.

FIGURE 2 is a front view of an embodiment of the invention with cover removed.

FIGURE 3 is a view of the left side of an embodiment of the invention with the cover removed.

FIGURE 4- is a view of the right side of an embodiment of the invention with the cover removed.

FIGURE 5 is a detail view.

FIGURE 6 is a schematic circuit diagram.

FIGURE 7 is a block diagram showing temperature sensitive means to automatically control the lamp temperature.

FIGURE 8 is a block diagram showing temperature sensitive means for automatically controlling the paper drive motor speed.

FIGURES 9 and 10 are schematic circuit diagrams showing alternate temperature sensitive means to automatically control the paper drive motor speed.

Referring to the figures, and more particularly to FIG- URE 1, the invention comprises a case 1, having a shelf 2 at the front and having an entry slot 3 for the papers located above the shelf 2. An exit slot 4 is provided at the near top of the machine and speed control 5 is provided to control the speed of the motor and therefore, the amount of heat applied to the papers. On-off switch 38 is also provided on the machine. A carrier which is a paper with a flap made of nylon mesh or a celluloid folder in which the copy material and original are inserted prior to their insertion within the machine, may be used as an accessory. Ventilation slots 32 are provided in the case It. The machine is a desk type approximately the size of a typewriter but having less height than a typewriter.

FIGURE 2 shows a front view of the machine with the casing removed and FIGURES 3 and 4 show left and right partial views with the casing removed. The lamp 6 is a long thin lamp having a quartz enclosure. It is mounted in a reflector 7 which is adapted to focus on the line of tangency between the glass roller 8 and pres sure roller 9.

The pressure roller 9 is mounted in suitable bearings on spring loaded members 9a on each side of the machine and is drivably connected with the glass roller 8. The glass roller 8 is rotatably mounted between the pressure roller 9 and the friction rollers 10 and II, which are suitably mounted on hearings on either side of the machine.

The lamp is stationary and is mounted on adjustable brackets on either side of glass roller 8. Each bracket has a fine lamp position adjustment screw 48. The roller it is driven by the motor 12 through a transmission 13, pulley 14 belt 15 and pulley 16 which is attached to the shaft of the roller lid. The rollers g, iii, and II are spaced to hold the glass roller 8 and drive the glass roller which in turn drives the pressure roller 9.

The paper P is inserted through the slot 3 on top of shelf 2 and passes between the internal guide members 17 and 13. A paper feeler member 29 is fixed on a rotatably mounted shaft Ztl and is lightly spring loaded by springs within switches 21 and 36 in the counter-clockwise direction of FIGURE 4.

A safety switch 6a is connected in series with the lamp 6 for the purposes of opening the lamp circuit if the rollers become jammed. The switch 6a is actuated by crank arm 4-2, FIG. 3, which is pivotally mounted on the frame adjacent the belt 15. The roller 43 on the end of the crank arm is spring loaded against the belt 15. If the roller becomes jammed for any reason, the belt will straighten out and the crank arm will rotate thereby opening switch 6a.

When the paper is inserted the forward projection 20a of the feeler 2h is rotated clockwise in FIGURE 4 by the leading edge of the paper and the feeler member is held in this position until the trailing edge of the paper passes the second projection 2% which is located as close as possible to the focal line of tangency of the rollers S and 9. A pair of snap action switches 21 and as are actuated by a bend in the shaft 2%. Switch Zll is connected in series with the lamp 6 so that the lamp will be on while the paper is passing the rollers 3 and 5?. This arrangement avoids the necessity of any relays for controlling the lamp current. The switch is of a type which will directly control the considerable lamp current.

The paper P is then guided by the guide members 24 and 25, which are suitably attached to the frame of the machine, to the exit slot 4. Therefore, the paper traverses an S-type curve P. This minimizes the slippage between the papers. There are either two papers used in the direct transfer process or three papers when a carbon transfer paper is used and there is a tendency of the papers to slip relative one another.

This minimizes the slippage between the papers because the greater-radius paper changes as the paper passes through the rollers. In prior machines, the paper goes through a bend and ejects at the top of machine above the line of tangency. With the prior arrangement, one paper has the greatest radius of movement at all times and therefore, slippage between the papers at the crucial point of heat focus causes blurring of the image. With the present system, the paper travels in an S-curve, one paper has the greater radius and then the other paper, so that the possibility of relative motion between constituent media of the copying process is minimized.

Referring also to FIGURE 4, a cylindrical turbine type fan 30 is provided at the lower rear of the machine which draws air from the. back of the machine through an aperture 31 and pushes air forward along the bottom of the machine where it exits through ventilation apertures 32 in the forward portion of each side of the machine. This provides the maximum cooling in the lamp area and prevents the case of the machine from becoming uncomfortably hot. However, it is not sufiicient to maintain the interior of the machine to a constant temperature. Therefore, after several consecutive copies, the interior of the machine gradually heats up.

In order to provide uniform copies, the application of heat to the papers must be made uniform. As the machine heats up, the papers must be driven faster by the motor drive in order to provide uniform copy. Therefore, the motor run is on DC. during the copying process. Referring to FIGURE 6, the system is controlled by the circuit comprising a potentiometer 33 connected to speed control knob 5, rectifier 34 and SCR silicon control rectifier 35. The rectifier provides pulsating D.C. control voltage to the motor 12 when the switch 36 is in the left or run position, and provides various speeds to accommodate various types of copy media. The circuity is arranged to maintain constant speed during slight changes in mechanical load on the motor. Please note that the lamp 6 and the DC). motor are connected in parallel across the line. Therefore, if the voltage regulatign is poor and the voltage drops, then the intensity of the lamp will also drop. Since the DC. motor is sensitive to the lower voltage, it will slow down which tends to compensate for lower intensity of the lamp, so that the applied heat tends to average. Conversely, if the voltage goes up, then the lamp will become brighter and the motor will also speed up so that the amount of heat applied to the paper tends to average.

When the switch 36 is in the right hand position, it is connected to the AC. voltage and idles at a speed predetermined by the adjustable resistor 37. The switch 36 is actuated by the paper feelers on shaft 20 to run position.

The on-off switch 3% has two poles. When the switch is turned to on position, the fan 30 and motor control circuits are energized through one pole of switch 38. Therefore, when the machine is on and there is no paper in the machine, the rollers idle on A.C. This avoids the development of hot spots on the roller which may cause lines on the copy paper. Pilot lamp 38 which may be a neon lamp lights to show when voltage is applied to the lamp 6 circuit. Potentiometer 29 is a minimum speed adjustment.

The lamp 6 is energized through feeler operated switch 21 which is connected to the other pole of switch 38. Switch 21 is actuated by feeler shaft 20. A thermostat switch 39 is connected parallel with the motor pole of switch 38 in order to keep the machine operating after the switch 38 is turned to off or open position. The purpose of this is to keep the roller operating until the machine cools down sufliciently so that the glass roller 8 would not burn or otherwise damage the pressure roller 9 when it comes to rest, and prevent print striping. The thermostat 39 is of a conventional type which may be set in predetermined manner to accomplish this result.

FIGURE 5 shows a detail view of the lamp mounting and mounting for the pressure roller 9. The lamp 6 is mounted on a stationary adjustable bracket 40 and a corresponding bracket on the other side which are mounted on each side of the machine, outside the ends of the glass roller 8. The lamp 6 has a reflector which may be finished in gold or other highly reflective material which is adapted to focus the lamp 6 along the line of tangency between the rollers 8 and 9.

The pressure roller is rotatably mounted on the bracket Qa which is pivotally mounted on the bracket 9b which is attached to the floor of the machine. There is a corresponding mounting on the other side. The bracket 9a is spring loaded forward against the glass roller 8 by spring 9c. The roller 9 is a pressure type roller which has a covering material which is heat resistant such as neoprene, silicon rubber, fluoro-silicon rubber, Teflon (tetrafiuoroethylene) or other equivalent resistant materials. This heat resistant material is chosen and the temperature of the machine is controlled so that no hot spots develop between the glass roller 8 and the pressure roller 9 such as would cause burning or blistering of the pressure roller 9.

FIGURE 7 shows means for automatically controlling the lamp temperature. These means include a conventional temperature sensing device 40, located adjacent the lamp, which is connected to amplifier 41 for controlling a current controlling device 42 which is connected in series with the lamp. The circuit of FIGURE 7 would be inserted in FIGURE 6 by removing lamp 6 in FIGURE 6 and connecting wires left unconnected when lamp 6 was removed from FIGURE 6.

FIGURE 8 shows means for controlling the paper drive motor 12 speed. This means comprises a temperature sensing device 43 which is connected through an amplifier 44 to the motor 12. The element 43 is mounted close to lamp 6 and amplifier 44 would be connected to the top of motor 12 of FIGURE 6.

FIGURE 9 shows alternate means for controlling the motor speed. This means includes a temperature sensitive resistor means 45 which is connected in series with the speed control 33 for the motor. Various conventional devices are available which change resistance proportional to temperature including silicon type devices.

FIGURE 10 shows another modification for controlling the motor speed incorporating a potentiometer 47 which incorporates a bi metal sensing element 46. Therefore as the temperature changes, the amount of resistance changes. The device 47 may be substituted for the temperature sensitive resistor 45 in FIGURE 9. Resistors 45 in FIG- URE 9 and 49 in FIGURE 10 are intended to replace rheostat 29 in FIGURE 6.

The motor speed would be manually selected at potentiometer 33 and would be automatically maintained by the automatic temperature control.

These automatic control means would eliminate the necessity for manually changing the speed control as the machine is used.

Therefore, the present invention provides a compact quiet dry copy machine which is simple to operate and does not require any chemicals. The machine is light weight and easy to move and has very simplified controls and rugged construction with a minimum of moving parts. All complicated relays of prior machines are eliminated. The machine makes clear, legible copies either directly or with a carbon transfer paper in about two seconds. The machine may also make transparent copies and off set copies for duplicating machines. The device also can be used for laminating important papers between plastic sheets.

Many modifications may be made by those who desire to practice the invention without departing from the scope thereof which is defined by the following claims.

We claim:

1. A dry copy machine comprising a housing, a stationary elongated heat lamp,

a hollow glass roller,

means to rotatably mount said glass roller in enclosing relation to said lamp,

means to adjust the position of said lamp with respect to said glass roller,

a pressure roller mounted in driven engagement with said glass roller,

means to focus the heat from said lamp along the line of said tangency of said rollers,

means to rotate said rollers comprising,

motor means including a control switch for energizing said motor,

means to control the speed of said motor means, said last means providing a normal operating speed and an idle speed,

means to guide papers between said rollers at normal speed,

sensing means located in the path of said papers before they pass between said rollers, connected to a switch which is connected to energize said lamp only when said paper is passing between said rollers and said sensing means is in contact with said paper,

said paper guide means being arranged in an S-curve under one of said rollers and over the other of said rollers so that the papers follow an S-curve from a substantially horizontal plane below said one roller in a direction of approximately 45 from said horizontal plane and between said rollers and then through a reverse curve over the top of said other roller to an aperture at the top of said housing located behind said other rollers, and

means to prevent hot spots on said rollers comprising means including a second switch operated by said sensing means when papers are not in contact with said sensing means for causing the motor to drive said rollers at said idle speed during the period when the paper is not passing through the machine.

2. A dry copy machine comprising a housing,

a stationary elongated heat lamp,

a hollow glass roller,

means to rotatably mount said glass roller in enclosing relation to said lamp,

means to adjust the position of said lamp with respect to said roller,

a pressure roller mounted in driven engagement with said glass roller,

means to focus the heat from said lamp along the line of said tangency of said rollers,

means to rotate said rollers comprising,

motor means including a control switch for energizing the motor,

means to control the speed of said motor means,

said last means providing a normal operating speed and an idle speed,

means to guide papers between said rollers,

sensing means located in the path of said papers before they pass between said rollers connected to a first switch which is connected to energize said lamp only when said paper is passing between said rollers and said sensing means is in contact with said paper,

said paper guide means being arranged in an S-curve under one of said rollers and over the other of said rollers so that the papers follow an S-curve from a substantially horizontal plane below said one roller in a direction of approximately 45 from said horizontal plane, and between said rollers and then through a reverse curve over the top of said other roller to an aperture at the top of said housing located behind said other roller,

means to prevent hot spots on said rollers comprising means including a second switch operated by said sensing means when paper is not in contact with said sensing means for causing the rollers to idle during the period when the paper is not passing through the machine,

and thermostat control means responsive to temperature of said area of tangency of said rollers connected in parallel with said motor means control switch, to keep said roller at an idle speed after the machine is turned oil until said rollers fall to a predetermined temperature sufiiciently low to prevent hot spots or damage to said rollers when they come to a stop.

3. A dry copy machine comprising a housing,

a stationary elongated heat lamp,

a hollow glass roller,

means to rotatably mount said glass roller in enclosing relation to said lamp,

means to adjust the position of said lamp relative to said roller,

a pressure roller mounted in driven engagement with said glass roller,

means to focus the heat from said lamp along the line of tangency of said rollers,

means to rotate said rollers comprising,

motor means including a control switch to energize said motor,

means to control the speed of said motor means,

said last means providing a normal operating speed and an idle speed,

means to guide papers between said rollers,

sensing means located in the path of said papers before they pass between said rollers connected to a switch which is connected to energize said lamp only when said paper is passing between said rollers and said sensing means is in contact with said paper,

said paper guide means having a first portion in feeding relation to said rollers, a second portion in paper receiving relation from said rollers, said first and second portions lying in planes substantially parallel to each other, the paper passing through said area of tangency at substantially 45 to the planes or" said portions,

means to prevent hot spots on said rollers comprising means including a second switch operated by said sensing means when paper is not in contact with said sensing means for causing the rollers to idle during the period when the paper is not passing through the machine,

and thermostat control means responsive to temperature of said area of tangency of said rollers connected in parallel with said motor means control switch to keep said rollers at an idle speed after the machine is turned off until said rollers fall to a predetermined temperature sufficiently low to prevent damage to said rollers when they come to a stop,

said motor speed control means including a DC. speed control having a silicon controlled rectifier.

4. A dry copy machine comprising a housing,

a stationary elongated heat lamp,

a hollow glass roller,

means to rotatably mount said glass roller in enclosing relation to said lamp,

means to adjust the position of said lamp with respect to said roller,

a pressure roller mounted in driven engagement with said glass roller,

means to focus the heat from said lamp along the line of said tangency of said rollers,

means to rotate said rollers comprising,

motor means including a control switch for energizing said motor,

means to control the speed of said motor means,

said last means providing a normal operating speed and an idle speed,

means to guide papers between said rollers,

sensing means located in the path of said papers before they pass between said rollers connected to a first switch which is connected to energize said lamp only when said paper is passing between said rollers and said sensing means is in contact with said paper,

said paper guide means having a first portion in feeding relation to said rollers, a second portion in paper receiving relation from said rollers, said first and second portions lying in planes substantially parallel to each other, the paper passing through said area of tangency at substantially 45 to the planes of said portions,

means to prevent hot spots on said rollers comprising means including a second switch operated by said sensing means when paper is not in contact with said sensing means for causing the rollers to idle during the period when the paper is not passing through the machine,

and thermostat control means responsive to the temperature of said area of tangency of said rollers connected in parallel with said motor means control switch to keep said roller at an idle speed after the machine is turned off until said rollers fall to a predetermined temperature sufficiently low to prevent damage to said rollers when they come to a stop,

said motor means speed control means including D.C. speed control having a silicon controlled rectifier,

said lamp being connected in series with said first switch which is directly controlled by said sensing means.

5. A dry copy machine comprising a housing,

a stationary elongated heat lamp,

a hollow glass roller,

means to rotatably mount said glass roller in enclosing relation to said lamp,

means to adjust the position of said lamp with respect to said roller,

means to focus the heat from said lamp along the line of said tangency of said rollers,

means to rotate said rollers comprising,

motor means including a control switch to energize said motor means,

means to control the speed of said motor means,

said last means providing a normal operating speed and an idle speed,

means to guide papers between said rollers,

sensing means located in the path of said papers before they pass between said rollers, connected to a switch which is connected to energize said lamp and said sensing means is in contact with said paper, said paper guide means having a first portion in feeding relation to said rollers, a second portion in paper receiving relation from said rollers, said first and second portions lying in planes substantially parallel to each other, the paper passing through said area of tangency at substantially 45 to the planes of said portions,

means to prevent hot spots on said rollers comprising means including a second switch operated by said sensing means when paper is not in contact with said sensing means for causing the rollers to idle during the period when the paper is not passing through the machine,

thermostat control means responsive to temperature of said glass roller connected in parallel with said motor means control switch to keep said rollers at said idle speed after the machine is turned off until said rollers fall to a predetermined temperature suificiently low to prevent damage to said rollers when they come to a stop,

said motor means speed control meansincluding D.C. speed control having a silicon controlled rectifier,

said lamp being connected in series with said first switch which is controlled by said sensing means,

and means responsive to stopping of said rollers by jamming, for turning off said lamp.

6. A dry copy machine comprising a housing,

a stationary elongated heat lamp,

a hollow glass roller,

means to rotatably mount said glass roller in enclosing relation to said lamp,

means to adjust the position of said lamp with respect to said roller,

a pressure roller mounted in driven engagement with said glass roller,

means to focus the heat from said lamp along the line of said tangency of said rollers,

means to rotate said rollers comprising,

motor means including a control switch for energizing said motor means,

means to control the speed of said motor means,

said last means providing a normal operating speed and an idle speed,

means to guide papers between said rollers,

sensing means located in the path of said papers before they pass between said rollers, connected to a switch which is connected to energize said lamp only when said paper is passing between said rollers and said sensing means is in contact with said paper,

said paper guide means having a first portion in feed ing relation to said rollers, a second portion in paper receiving relation from said rollers, said first and second portions lying in planes substantially parallel to each other, the paper passing through said area of tangency at substantially to the planes of said portions,

means to prevent hot spots on said rollers comprising means including a second switch operated by said sensing means when paper is not in contact with said sensing means for causing the rollers to idle during the period when the paper is not passing through the machine,

thermostat control responsive to temperature of the area of tangency of said rollers connected in parallel with said motor means control switch to keep said roller at an idle speed after the machine is turned off until said rollers fall to a predetermined temperature sufiiciently low to prevent damage to said rollers when they come to a stop,

said motor means speed control means including D.C. speed control having a silicon controlled rectifier,

said lamp being connected in series with said first switch which is directly controlled by said sensing means,

means responsive to stopping of said rollers by jamming,

for turning off said lamp,

said sensing means comprising,

first finger means adapted to be actuated by the leading edge of said papers,

and second finger means adapted to be actuated by the trailing edge of said papers,

said second means being located close to the line of tangency of said rollers,

means connecting said first and second means to said switch which is connected in series with said lamp for operating said switch to turn the lamp on and oh.

References Cited by the Examiner UNITED STATES PATENTS 2,891,165 6/1959 Kuhrmeyer et al. 250 2,900,889 8/1959 Iaffe et al. M 77.5 3,128,379 4/1964 Cisek et al. 250-65 3,150,262 9/1964 Ulseth et al. 25065 3,165,688 1/1965 Gutzwiller 318-246 RICHARD M. WOOD, Primary Examiner.

ANTHONY BARTIS, Examiner. 

1. A DRY COPY MACHINE COMPRISING A HOUSING, A STATIONARY ELONGATED HEAT LAMP, A HOLLOW GLASS ROLLER, MEANS TO ROTATABLY MOUNT SAID GLASS ROLLER IN ENCLOSING RELATION TO SAID LAMP, MEANS TO ADJUST THE POSITION OF SAID LAMP WITH RESPECT TO SAID GLASS ROLLER, A PRESSURE ROLLER MOUNTED IN DRIVEN ENGAGEMENT WITH SAID GLASS ROLLER, MEANS TO FOCUS THE HEAT FROM SAID LAMP ALONG THE LINE OF SAID TANGENCY OF SAID ROLLERS, MEANS TO ROTATE SAID ROLLERS COMPRISING, MOTOR MEANS INCLUDING A CONTROL SWITCH FOR ENERGIZING SAID MOTOR, MEANS TO CONTROL THE SPEED OF SAID MOTOR MEANS, SAID LAST MEANS PROVIDING A NORMAL OPERATING SPEED AND AN IDLE SPEED, MEANS TO GUIDE PAPERS BETWEEN SAID ROLLERS AT NORMAL SPEED, SENSING MEANS LOCATED IN THE PATH OF SAID PAPERS BEFORE THEY PASS BETWEEN SAID ROLLERS, CONNECTED TO A SWITCH WHICH IS CONNECTED TO ENERGIZE SAID LAMP ONLY WHEN 